Single-Nanoparticle-Level Understanding of Oxidase-like Activity of Au Nanoparticles on Polymer Nanobrush-Based Proton Reservoirs

Enzyme-mimickingnanoparticles play a key role in importantcatalyticprocesses, from biosensing to energy conversion. Therefore, understandingand tuning their performance is crucial for making further progressin biological applications. We developed an efficient and sensitiveelectrochemical method for the real-time monitoring of the glucoseoxidase (GOD)-like activity of single nanoparticle through collisionevents. Using brush-like sulfonate (-SO3 (-))-doped polyaniline (PANI) decorated on TiO2 nanotubearrays (TiNTs-SPANI) as the electrode, we fabricated a proton reservoirwith excellent response and high proton-storage capacity for evaluatingthe oxidase-like activity of individual Au nanoparticles (AuNPs) via instantaneous collision processes. Using glucose electrocatalysisas a model reaction system, the GOD-like activity of individual AuNPscould be directly monitored via electrochemical teststhrough the nanoparticle collision-induced proton generation. Furthermore,based on the perturbation of the electrical double layer of SPANIinduced by proton injection, we investigated the relationship betweenthe measured GOD-like activities of the plasmonic nanoparticles (NPs)and the localized surface plasmon resonance (LSPR) as well as theenvironment temperature. This work introduces an efficient platformfor understanding and characterizing the catalytic activities of nanozymesat the single-nanoparticle level.

Automated summary

Enzyme-mimicking nanoparticles are crucial in catalytic processes, and understanding and tuning their performance is important for biological applications. Researchers developed an efficient electrochemical method for monitoring the glucose oxidase-like activity of single nanoparticle through collision events. They used brush-like sulfonate-doped polyaniline decorated on TiO2 nanotube arrays as the electrode and evaluated the oxidase-like activity of individual Au nanoparticles through collision-induced proton generation. By investigating the perturbation of the electrical double layer of the nanoparticles, the relationship between the measured oxidase-like activities and the localized surface plasmon resonance and temperature was revealed.